Datlist multiple sort not working on live site

Silverstripe Version: 4.1.1

Question: Hi all, i got this function in my controller which sorts on deadline first and then on reference. Works fine on my localhost, but when i deploy, navigating to the page says “The requested page cannot be found” (NOT a 404 page, it just echoes it). If i sort only on deadline, it works fine on the live site too. Can someone help me out pls?

Details of your query go here

/public function getMyVacancies() {
        return datalist::create('\pena\myrrha\VacancyPage')
               'ParentID' => $this->ID,
               'Deadline:GreaterThanOrEqual' => date("Y-m-d")
                'Deadline' => 'ASC',
                'Reference' => 'ASC'

Could it be that your local mysql version is 5.6 and the one on the servers is 5.7? If so here is the solution: Fixing MySQL 5.7 troubles